A series of monoclonal antibodies were raised by immunization with a malignant human lymphoblastoid T cell line. This panel includes antibodies specific for differentiation-associated antigens expressed either by basal keratinocytes; by the stratum corneum and cells in the stratum granulosum; or by all epidermal keratinocytes. Further characterization of their tissue distribution will be performed by immunoperoxidase studies of tissue sections, and immunofluorescence studies of lymphoid cells and keratinocytes in vitro. The functions of these antigens will be investigated in both epidermal and lymphocyte systems in vitro. Characterization and purification of these antigens will be done by SDS-PAGE analysis and affinity chromatography. These monoclonal antibodies are being applied to localize abnormalities in keratinization that occur in diseases of altered epidermal differentiation, e.g., psoriasis. In psoriatic skin, evidence has been obtained for abnormal patterns of epidermal reactivity with our monoclonal antibodies. These abnormalities revert to the normal pattern with successful in vivo-administered therapy. These studies of psoriasis will be enlarged and extended to other diseases characterized by abnormal epidermal differentiation. Additionally, these antibodies will be used to study the effect of retinoids, which are used to treat psoriasis, pityriasis rubra pilaris and certain of the ichthyosiform dermatoses, upon in vitro keratinocyte differentiation. Finally, basal keratinocyte specific antibodies, which react with cell surface membrane antigens, will be used to purify basal epidermal keratinocytes. In vitro cultures of purified basal keratinocytes will be established and used as autologous grafts in patients with dystrophic epidermolysis bullosa and other chronic, nonhealing wounds.